Advertisements
Advertisements
प्रश्न
Find the mean of 75 numbers, if the mean of 45 of them is 18 and the mean of the remaining ones is 13.
उत्तर
Mean of 45 numbers = 18
⇒ Sum of 45 numbers = 18 x 45 = 810
Mean of remaining ( 75 - 45 ) 30 numbers = 13
⇒ Sum of remaining 30 numbers = 13 x 30 = 390
⇒ Sum of all the 75 numbers = 810 + 390 = 1200
⇒ Mean of all the 75 numbers = `1200/75` = 16
APPEARS IN
संबंधित प्रश्न
In a series of tests, A appeared for 8 tests. Each test was marked out of 30 and averages 25. However, while checking his files, A could only find 7 of the 8 tests. For these, he scored 29, 26, 18, 20, 27, 24 and 29.
Determine how many marks he scored for the eighth test.
Find the mean of all factors of 10.
The mean marks (out of 100) of boys and girls in an examination are 70 and 73 respectively. If the mean marks of all the students in that examination are 71,
find the ratio of the number of boys to the number of girls.
The mean weight of 120 students of a school is 52.75 kg. If the mean weight of 50 of them is 51 kg,
find the mean weight of the remaining students.
The mean of 200 items was 50. Later on, it was discovered that two items were misread as 92 and 8 instead of 192 and 88.
Find the correct mean.
If different values of variable x are 9.8, 5.4, 3.7, 1.7, 1.8, 2.6, 2.8, 8.6, 10.5 and 11.1;
find
(i) the mean ` barx `
(ii) the value of ` sum (x_i - barx)`
The mean of 16 numbers is 8. If 2 is added to every number, what will be the new mean?
The mean of 40 observations was 160. It was detected on rechecking that the value of 165 was wrongly copied as 125 for computation of mean. Find the correct mean.
The mean of 100 items was found to be 30. If at the time of calculation two items were wrongly taken as 32 and 12 instead of 23 and 11, find the correct mean.
If `bar"X"` is the mean of n observations x1, x2, x3,..., xn then the mean of `x_1/"a", x_2/"a", x_3/"a",...,x_"n"/"a" "is" bar"X"/"a"`, where a is an non-zero number.
i.e., if each observation is divided by a non-zero number, then the mean is also divided by it.
